<!DOCTYPE html>
<html lang="zh-CN">
<head>
    <meta charset="UTF-8">
    <title>11_margin的注意事项</title>
    <style>
        .outer {
            width: 200px;
            /* height: 200px ; */
            background-color: aqua;
        }
        .inter {
            width: 100px;
            height: 100px;
            background-color: coral ;
            margin-top: 100px;
            
        }
        .bottom {
            width: 100px;
            height: 100px;
            background-color: rgb(130, 80, 255) ;
            margin-bottom: 20px;
        }
    </style>
</head>
<body>
    <!-- 子元素里的margin是参考在父元素的content计算的 -->
    <div class="outer">
        <div class="inter">1</div>
        <div class="bottom">2</div>
    </div>
    <span>3</span>
</body>
</html>